content: /*
   * Copyright 2019 David Karnok
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package hu.akarnokd.rxjava3.jdk8interop;
  
  import java.util.Optional;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.disposables.Disposable;
  import io.reactivex.rxjava3.exceptions.Exceptions;
  import io.reactivex.rxjava3.functions.Function;
  import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
  import io.reactivex.rxjava3.internal.functions.ObjectHelper;
  
  /**
   * Maps the success value of the source Maybe into an Optional and emits this Optional's value if present,
   * otherwise terminates.
   *
   * @param <T> the upstream value type
   * @param <R> the result value type
   */
  final class MaybeMapOptional<T, R> extends Maybe<R> {
  
      final MaybeSource<T> source;
  
      final Function<? super T, Optional<R>> mapper;
  
      public MaybeMapOptional(MaybeSource<T> source, Function<? super T, Optional<R>> mapper) {
          this.source = source;
          this.mapper = mapper;
      }
  
      @Override
      protected void subscribeActual(MaybeObserver<? super R> observer) {
          source.subscribe(new MapOptionalObserver<>(observer, mapper));
      }
  
      static final class MapOptionalObserver<T, R> implements MaybeObserver<T>, Disposable {
  
          final MaybeObserver<? super R> actual;
  
          final Function<? super T, Optional<R>> mapper;
  
          Disposable d;
  
          public MapOptionalObserver(MaybeObserver<? super R> actual, Function<? super T, Optional<R>> mapper) {
              super();
              this.actual = actual;
              this.mapper = mapper;
          }
  
          @Override
          public void dispose() {
              d.dispose();
          }
  
          @Override
          public boolean isDisposed() {
              return d.isDisposed();
          }
  
          @Override
          public void onSubscribe(Disposable d) {
              if (DisposableHelper.validate(this.d, d)) {
                  this.d = d;
  
                  actual.onSubscribe(this);
              }
          }
  
          @Override
          public void onSuccess(T value) {
              Optional<R> v;
  
              try {
                  v = ObjectHelper.requireNonNull(mapper.apply(value), "The mapper returned a null Optional");
              } catch (Throwable ex) {
                  Exceptions.throwIfFatal(ex);
                  actual.onError(ex);
                  return;
              }
  
              if (v.isPresent()) {
                  actual.onSuccess(v.get());
              } else {
                  actual.onComplete();
              }
          }
  
          @Override
          public void onError(Throwable e) {
              actual.onError(e);
          }
  
          @Override
          public void onComplete() {
              actual.onComplete();
          }
  
      }
  }
  